Flywheel/Flex Plate and Ring Gear

Flex plate is the term for a flywheel mated with an automatic transmission.

REMOVAL AND INSTALLATION

2.2L, 2.6L and 3.0L Engines

See Figures 1, 2 and 3

The ring gear is replaceable only on engines mated with a manual transmission. Engine with automatic transmissions have ring gears which are welded to the flex plate.

Remove the transmission and, on 4WD, the transfer case.

Fig. Fig. 1: Lock the flywheel in place and remove the retaining bolts ...

Fig. Fig. 2: ... then remove the flywheel from the crankshaft

Remove the clutch, if equipped, or torque converter from the flywheel. The flywheel bolts should be loosened a little at a time in a cross pattern to avoid warping the flywheel. On trucks with manual transmission, replace the pilot bearing in the end of the crankshaft if removing the flywheel.

The flywheel should be checked for cracks and glazing. It can be resurfaced by a machine shop.

If the ring gear is to be replaced, drill a hole in the gear between two teeth, being careful not to contact the flywheel surface. Using a cold chisel at this point, crack the ring gear and remove it.

Polish the inner surface of the new ring gear and heat it in an oven to about 600°F (315°C). Quickly place the ring gear on the flywheel and tap it into place, making sure that it is fully seated.

Never heat the ring gear past 800°F (426°C), or the tempering will be destroyed.

Fig. Fig. 3: Upon installation, apply a thread-locking compound to the flywheel bolts

Installation is the reverse of removal. Coat the bolt threads with sealant. To install the flywheel, first put it into position and then install the bolts loosely.

Tighten the bolts in sequence across from each other to the following specifications:

2.2L engine: 71-76 ft. lbs. (96-103 Nm)

2.6L engine (1987-88): 94-101 ft. lbs. (127-137 Nm)

2.6L engine (1989-93): 67-72 ft. lbs. (91-98 Nm)

3.0L engine: 76-81 ft. lbs. (103-109 Nm)

4.0L Engine

See Figures 1, 2 and 3

Remove the transmission, following procedures in Chapter 7, Clutch and Transmission.

On a manual shift transmission, remove the clutch pressure plate and cover assembly and clutch disc, following the procedures in Chapter 7, Clutch and Transmission.

Remove the flywheel attaching bolts and remove the flywheel.

To install:

Position the flywheel on the crankshaft flange. Coat the threads of the flywheel attaching bolts with Loctite® or equivalent and install the bolts. Tighten the bolts in sequence across from each other to 50-55 ft. lbs. (68-74 Nm).

On a manual shift transmission, install the clutch disc and pressure plate and cover assembly following the procedures in Chapter 7, Clutch and Transmission.

Install the transmission following the procedure in Chapter 7, Clutch and Transmission.

RING GEAR REPLACEMENT

This procedure is for manual shift transmission only. On automatic transmission if the ring gear has worn, chipped or cracked teeth, replace the flywheel assembly.

Heat the ring gear with a blow torch on the engine side of the gear, and knock it off the flywheel. Do not hit the flywheel when removing the ring gear.

Heat the new ring gear evenly until the gear expands enough to slip onto the flywheel. Make sure the gear is properly seated against the shoulder. Do not heat any part of the gear more than 500 degrees F. If this limit is exceeded, the hardness will be removed from the ring gear teeth.